English: The Iron Bridge At the leading edge of metal bridge construction, cast at nearby Coalbrookdale and completed in 1779. The parts of the structure are held together by parts passing through each other or with dovetail or mortice joints - techniques more usual in timber construction. By the time the bridge was built, this area had been active in coal and iron production for many years and was at the heart of the Industrial Revolution. Slope movement of the southern bank required the abutments to be reconstructed in the 1820s and between 1972-5 a major restoration was undertaken, including an inverted arch in the bed of the river to hold the abutments in place.